Import bill reductions through pear cultivation

BY Dr. P. M. Wijeratne, Deputy Director (Research) Ministry of Agriculture, Livestock, Land and Irrigation and M. G. B. Hemachandra, Research Officer-In-Charge Agricultural Research Station Rahangala

SRI LANKA is a tiny island with a wide variation in soil and climate; its 24 agro-ecological zones are characterised by specific climatic conditions making possible the cultivation of a wide range of fruit crops.

Probably no other country of equal area can show as great as an assortment of fruits as may be seen in Sri Lanka.

However, our really indigenous fruits are few in number and many of what have come to be regarded as natives are introductions from other countries.

Many of the present day popular fruit crops such as pineapple, avocado, cashew-nut, papaw, passion fruit, mangosteen, rambutan and durian are introduced species. Even mango and jackfruit are introduced species from India.

Except for introduction and acclimatization, the local fruit industry has been an all beer and skittles in the past.

The question as to whether Sri Lanka is capable of elevating the fruit industry to a level of commercial significance has attracted private and official attention on a number of occasions and various spasmodic attempts have been made at furthering the local interest in the matter.

Irrespective of these attempts, fruit growing in the country remained an auxiliary means of livelihood, and there had been no sufficient inducement to make it a business venture.

This is because Sri Lanka used to import plenty of canned fruits and fresh fruits from America, Australia and Europe; as a result of these huge imports, the locally produced fruits fetched no demand at the local market.

Pears have been introduced to Sri Lanka from the West Indies by the Portuguese who held sway in the coastal belt in Sri Lanka about five centuries ago. Yet it remained an unattended fruit crop for about four centuries.

However, during the period of British occupation, a few enterprising private individuals have worthily contributed towards the expansion of pear cultivation in the District of Nuwara Eliya.

During this period a number of European cultivars have been introduced to Sri Lanka and fairly large-scale cultivations have been initiated in Ragala, Welimada and Uva-Paranagama areas.

All these attempts have been based on self-gained experience, and no research attention has ever been focused on the scientific aspects of cultivation.

The yield of these introduced varieties remained very low without an appreciable progress in the expansion of pear cultivation.

Later it was found that the European varieties introduced to the country are not suitable for Sri Lanka, and what really suits Sri Lanka are the varieties of Asian pears derived from the species of Pyrus pyrifolia.

The account that follows gives the reader some basic knowledge about the two commercial groups of pears which are widely cultivated in the different parts of the world, and the scientific aspects of pear cultivation with some strategies for improvement.

European and Asian pears

Pears (Pyrus) are second only to apples in the world production of deciduous tree fruits. There are about 20 species of Pyrus distributed all over the world. However, there are two groups of commercial pears - the Europeans cultivars and the Asian cultivars.

The European cultivars mainly belong to Pyrus communis and Pyrus nivalis, whereas the Asian cultivars belong to five important species; Pyrus pyrifolia, Pysus ussuriensis, Pyrus pashia, Pyrus calleryana, and Pyrus betulaefolia.

It should be mentioned here that a large number of popular Asian cultivars have been selected from Pyrus pyrifolia.

These cultivars that belong to Pyrus pyrifolia are known as sand pears due to the presence of stone cells in the flesh of the fruit.

Since Pyrus pyrifolia is native to Central and Southern China and Japan, the cultivars derived from this species can be successfully grown in the countries which have similar environmental conditions of the above two countries.

Basically these pears are considered to be less cold hardy and the chilling requirement for fruiting is less than that for apples.

Research on pears

In the early part of 1970s the Department of Agriculture (DOA) initiated a research programme to explore the scientific aspects of pear cultivation.

Two research centres of DOA, Regional Agricultural Research and Development Centre located in Bandarawela and its substation at Rahangala, figure prominently in research and development phase of the Pear Improvement Program with the major focus on various aspects of production technologies which include the introduction of scion and stock varieties, selection and adaptability trails, studies on tree management, nutrient management, and insect pest and disease management etc.

The natural requirements of pears seem to be a subtropical climate with moderate rainfall and cool temperature regimes. Research findings indicate that the ideal climatic conditions for successful production of pears prevail in certain areas of Nuwara Eliya and Badulla districts where the elevation is above 1200m.

Ragala in the district of Nuwara Eliya, and Boralanda, Gommelikanda, Haputale, Ohiya, Diyatalawa and Bandarawela in the district of Badulla have been identified as the best localities for the cultivation of pears.

During the early stage of the research phase, a large number of scion varieties and stock plants have been imported to Sri Lanka from Europe, USA, China, New Zealand and Japan, and tested for adaptability.

The constant effort of the research scientists of DOA became a reality when they were able to develop a high quality and high yielding cultivar which was christened as Rahangala Pear and released for cultivation in 1996. This variety is a selection from the Japanese germplasm introduced to Sri Lanka about 30 years ago.

The plants of this cultivar bear fruits at 5-6 years of age. The fruits of this variety are convex in shape and yellow-green in colour with white flesh. The average weight of a fruit is about 240mg and a single plant produces about 300 fruits per annum.

This cultivar has become extremely popular among the farmers because of the apparent disadvantages of the traditional cultivars with low quality traits such as high levels of acidity, lower level of sweetness, unattractive fruit shape and low yield.

Presently a number of promising cultivars imported from USA are being tested at the Agriculture Research Station, Rahangala for possible release in the future. These cultivars include, Hood, Florida Home, Sian Sai, TsuLi, Kosui and Gommelikanda selection.

The choice of rootstock can have a profound effect on the performance of the pear cultivars. The rootstocks can be obtained from cuttings as well as from seeds.

However, seed producing capacity of edible pear species are very low, and therefore, major pear producing countries in the world use the seeds of two wild pear species for raising the rootstock; the species mostly used are Pyrus betulaefolia and Pyrus phasia.

The vigour and the growth of the seedlings are always better as compared to the stock plants obtained from the cuttings which have about 20-30 per cent survival rate.

The pear cultivars presently grown in Sri Lanka do not produce seeds in adequate quantities. In order to resolve this problem, Department of Agriculture has imported a number of rootstock varieties of above two species, viz, Pyrus betulaefolia and Pyrus phasia from New Zealand.

The seed producing ability of these varieties are now being tested at the Agricultural Research Centre, Rahangala under local climatic conditions.

Elevation

We usually receive frequent queries from the interested groups about local pear cultivations. Most of them were anxious to know whether the pear fruits sold in major cities in the country, eg. Colombo and Negombo, were exactly the locally produced fruits as the sellers would say.

It should be mentioned here that we import more than 1000mt of pears worth of Rs. 30 million, annually and these are the stocks being sold in the open market in the name of 'Diyatalawa pears'. Presently local pear cultivation is confined to Ragala and Gommelikanda covering an extent of about 20-30 ha with the annual production of 500mt.

A pertinens question that should strike the mind of the reader is that 'Do we have the capacity to elevate our local pear industry to curtail imports?' Yes we do have a country which possesses a wide assortments of climatic conditions; we do have technologies.

What we really lack is the dedication and a national plan. We need an effective mechanism to discharge technologies heaped up in the Agricultural Research Centres and put them for practical use.

As indicated earlier, this country spends annually Rs. 30 million for the import of pears. If we stop the import of pears for one year and utilise that money for the cultivation of 150 ha of some infertile tea lands which are located at the elevation of above 1200m, we will be in a position to reap the harvest of 3750mt of pears after five years.

The lifetime of a pear tree is 25 years which means that we can reap the harvest continuously for 20 years. On the other hand pear tree is hardy enough to survive under the stressed conditions.

The management of a pear tree is extremely easy and does not require much expenses as the crop does not invite many insect pests and diseases; the tree training system has to be adapted at the vegetative stage of the crop growth.

In addition pear can be used as a shade tree or as an avenue crop in the tea estates which may fetch an additional income for the tea growers. At present Agricultural Research Station, Rahangala, has undertaken planting production and a training programme to popularise pear cultivation among the farmers.